Leveling mechanism for fire ladders



Nov. 8, 1932. BQHLEN, JR 1,886,783

LEVELING MECHANISM FOR FIRE LADDERS Filed Sept. 5, 1929 2 Sheets-Sheet 1 I 7 k7 y dude 5411222, J11,

M am

Nov. 8, 1932.

(3. BOHLEN, JR

LEVELING MECHANISM FOR FIRE LADDERS Filed Sept. 5, 1929 2 Sheets-Sheet 2 lllllllllfijmll :TllllllllllllljFlIIlllIlllll lIlllllLEEjifig I 0mm. I Wm Patented Nov. 8, 1932 UNITE STATES A'ITT- INTERNATIONAL Moron Price COMPANY, 01E NEW YORK, N. Y., A CORPORATION OF DELAWARE LEVELING MECHANISM FOR HIRE LADDERS Application filed September 5, 1929. Serial No. 390,504. r

1mposes severe stresses thereupon and frequently gives rise to damaging results.

,An object of the invention,-therefore, is to provide a device for leveling the ladder and turntable carried upon a vehicle.

A further object is toincorporatea leveling mechanism of the above character in a ladder elevating and turntable orienting construction of an improved form, such elements being incorporated without impairing the serviceability of the elevating and orienting mechanism and being conveniently disposed with respect thereto.

A further object of the invention is to provide a device for automatically leveling a ladder of the above type.

Further objects, not specifically enumerated above, will be apparent as the invention is described in greater detail in connection with.

the accompanying drawings, wherein:

Figure 1 is a view in side elevatiom'cut away and partly in section showing a ladder elevating mechanism carried by a turntable and provided with means for varying the position of the platform, turntable and ladder with respect to the horizontal.

Figure 2 is a view in section, taken on line 2-2 of Figure 1, and looking in the direction of the arrows. V

Figure 3 1s a View showing a modified con struction, wherein an automatic means for varying the level of the ladder is provided. Figure 4 is a schematic view showing the wirin diagram incorporated in the construc tion siown in Figure 3 for controlling the direction of fluid pressure upon the leveling piston.

Referring to the abovedrawing s, adesignates a trailer frame upon which an annular ring a is; carried. This ring is journaled upon a fifth wheel (21?, carried by a tractor, by means of ball bearings a and teeth a are provided in the periphery of the ring at to enable the turntable to be oriented properly. A bearing ring a is-journaled on the ring a and carries a bracket a having a saddle portion a. Upon'the saddle portion, bearings b are provided and a turntable 0 is supportedon the'bearings through a bearing plate 61. The bearing plate is formed with a curvature, thecen'ter -of which coincides.

with the axis of an elevating shaft 0 which constitutes a portion of the'elevat'ing mechanism and extends within a gear box 0 Power is supplied to the mechanism within housing f by means of suitable mechanism within a housing 1, shown in Figure 1 of the draw- (drear box 0 is formed with a boss 0 having a bearing surface andran auxiliary hous ing f is provided withextension f having a flange f for engaging the bearing surface 0 An annular retaining plate a is carried by the gearbox and engages the flange 7' to permit rocking movement of the gear box '0 with re- A spect to the relativelystationary housing 7 without destroying the continuity of the housing for the elevating mechanism. The gear box 'is mounted upon the ladder pivot shaft 6 by means of arms 0 having reinforcing webs 0 Although housing 7 rotates about a vertical axis, it does not partakeof the rotative movement of the platform 0 and gear box 0 necessary to level theladder, and the con nection last described permits such relative rotation between'the' gear box and housing. Itwill be understood, of course, that the leveling axis passes through the housing 7 and shaft 0, the gearing arrangement in thebox being similar to that shown in the copending application Ser. No. 390,503, filed September 5,1929. a

- ,The'ladder e is mounted upon A-brackets 6 carried upon the platform 0 and is elevated by means of the mechanism carried within the gear box 0 and housing f, together with the armse and linksei I The bearing memberd is reenforced by suitable webs (Z and is formed with laterally extending cylindrical portions (Z for engaging the bearings Z). U-brackets g are secured to the upper portions of the laterally extending sides (Z of the bearing member cl, and thus secure the bearing member to the saddle and prevent dislodgment therefrom.

A worm segment 7b is carried by the platform 0 and is engaged by a worm 72, carried upon a bracket it upon the ring a This bracket is formed with spaced standards 71/ within which a shaft h is journaled, the worm h being splined to the shaft h. A bevel gear h is splined to the'shaft h and engages a bevel pinion h which is mounted upon a vertically disposed, manually operable shaft 7L Shaft h is journaled in the bracket 72, and it and in a bracket 71 carried upon the bracket 7L Hand wheel h enables the shaft h to be turned and thus varies the position of the segment h and platform 0 with respect to the ring a,

A second bearing member j is carried by the platform 0 and engages a bearing seat y upon the ring a This seat j and bearing member j have a bearing surface, the axis of which coincides with that of the shaft 0', similarly to the bearing surface upon the bearing member (Z. It will be seen, therefore, that the turntable and elevating mechanism is adequately supported upon the ring a which may be oriented with respect to the frame a.

In order that the ladder may be automatically leveled, a modified construction is shown in Figures 3 and 4:. In this form, the worm segment it and related manually operating mechanism is replaced by downwardly extending arms is, carried by the turntable 0.

Between these arms, a cylinder Z is carried oppositely extending arms Z on the cylinder engaging elongated slots is in the arms la.

A rod m is secured to the sides of the frame,

a at m and a piston m is secured to the rod m and is slidably carried withinthe cylinder Z. Flexible pipe lines a and n communicate with the cylinder Zupon opposite sides of the piston m and carry a fluid under pressure from a pump 0 driven by a reversing motor 0. Upon rotation of the motor in one direction, a fluid pressure is exerted upon one side of the piston, while upon rotation in the opposite direction, a fluid pressure is directed on the opposite side of the piston. This results in the movement of cylinder Z and arms is in the appropriate direction and the platform 0 is thus leveled by the proper movement of the arms. v

The lowest rung p of the ladder is preferably of hollow metal and carries a sealed tube 9 having terminals g, 9 and 9 A globule of: mercury g is sealed in thetube and is of sufficient size to connect contact 9 with either of contacts q or 9 depending upon the slope of the tube. If the ladder and tube are level, the globule of mercury will rest in a recess 9 and the motor 0 will not be energized. 1f the ladder is not level, contact Q3 will be automatically connected with either contacts 9' or Q2 and the motor will be driven in the desired direction to move arms to a vertical position.

While the invention has been described in connection with the specific construction sures in opposite directions on the arm,a motor for operating the last named means, reversing contacts on the ladder and connected with the motor, and means controlled by the level of the support for closing certain of the contacts.

2. A fire ladder operating means comprising a turntable, a ladder support carried by the turntable, a ladder on the support, means on the support to elevate the ladder, an arm carried by the support, meansto exert pressures in opposite directions on the arm, and means controlled by the inclination of the sup-. port to cause the last named means to exert a pressure on thearm.

. 3. A fire ladder operating means comprising a turntable, a ladder support, a ladder on i the support, a ladder elevating means on the support, a cradle on the turntable having'a curvature aboutthe axis of the ladder elevating means, a bearing member on the support and engaging the cradle, a second cradle and bearing on the turntable and support respectively, and having curvatures about the axis of the elevating means, and means to vary the inclination of the support with respect to the turntable.

41-. A fire ladder operating means compris ing a turntable, a ladder support, a ladder on thesupport, a ladder elevating means on the support, a. cradle on theturntable having a curvature about the axis of the ladder elevating means, a bearing member on the support and engaging the cradle, and means to vary the inclination of the supportwith respect to the turntable. I

5. A fire ladder operatingmeans comprising a turntable, a cradle carried by the turntable, a ladder support, a bearing member on the support engaging the cradle, a ladder on the support, means on the support to elevate the ladder, and means to move the support and bearing member with respect to the cradle 6. A fire ladder operating means comprising a turntable, a ladder support carried by the turntable, a ladder on the support, means on the support to elevate the ladder, and

means to vary the inclination of the support With respect to the turntable.

7. In a fire ladder operating means comprising a turntable having a ladder support and ladder pivoted on the support and lying in a normally lowered position, means on the support to elevate the ladder, means to mount the support upon the table for movement in a plane at right angles to the plane of the table, a Worm segment on the support in a plane parallel to the pivot axis of the ladder, a Worm on the turntable engaging the segment, and means to rotate the worm.

This specification signed this 3rd day of August, A. D. 1929.

CHARLES BOHLEN, JR. 

